Calculate the reaction rate if [Cl2] = 0.012M, [O2] = 0.250M and the rate constant is 2.54x at 25C.

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.

No is the answer to the question

Decomposition is the cycle at which bacteria breaks down any organic material into the soil

Ido not understand.